Embodiments relate to wireless data transmissions. For example, scheduling wireless transmission of segmented voice data.
In wireless packet data networks for services with low packet delay budget constraints (e.g., voice over IP (VoIP) or conversational video services), constraints (e.g., quality) may be observed. For example, constraints based on residual Block Error Rate (rBLER) and packet transfer delays may be observed.
In poor radio coverage scenarios (e.g., user equipment on cell edges) when the packet data scheduler struggles to maintain an Initial Block Error Rate (iBLER) performance, the packet data scheduler provides for the transmission of VoIP packet data under a constraint that the total amount of power used for the transmission cannot be increased (e.g., current transmissions are at maximum power). In such a scenario, the typical behavior of the radio interface packet data scheduler is to instruct the user equipment to segment the packets which allows for the use of a more robust Modulation and Coding Scheme (MCS) for the transmission of each individual packet (e.g., less data is transmitted over a time interval which requires less power for transmission).
The number of payload bits per transmission is consequently reduced, thereby increasing the amount of power per transmitted bit. This leads to an improved iBLER performance.
However, packet segmentation introduces delay to the transmission of the packet by the user equipment and introduces a bottleneck to the maximum useful bit rate that can be achieved on the radio link (because the number of bits per transmission time interval (TTI) is restricted). Beyond a critical level of segmentation (i.e. below a minimum payload size per TTI) the radio link throughput becomes lower than the service data rate; and the overall packet delay starts to build up (e.g., accumulate) inferring that the support of the service with low packet delay constraint is no longer viable.
This “uncontrolled packet segmentation” by the user equipment requires the user equipment to add an additional header to facilitate the reassembly of the packet at the receiver (e.g., eNodeB). Higher levels of segmentation lead to higher ratios of overhead, which degrades the efficiency of the transmission. Further, beyond a critical level of segmentation (i.e. below a minimum payload size per TTI), the radio link throughput becomes lower than the service data rate and the overall packet delay start to build up (e.g., accumulate) inferring that support of the service with low packet delay constraint is no longer viable.